It is well-established European law that the combination of two specific features each selected from different lists “of some length” may result in a novel invention when combined. This principle, the “two-list principle” as established in T 12/81 is outlined in detail here.
In the recently published decision T 2635/16 from the European Patent Office, the Board considers what constitutes a selection in the lists of the prior art.
In this case, Claim 1 of the patent was directed to a specific salt of a specific compound. During prosecution, the Examiner cited document D1 as novelty destroying to Claim 1. D1 related to compounds of a general formula or salts thereof and disclosed the specific compound in one of its claims, amongst a list of 121 other compounds. Separately, D1 disclosed the specific salt in a list of possible salts, the list of salts referred to the general claimed formula and not the claimed compounds. The Examiner considered that the disclosure of the specific compound in the claims of D1 meant it was a highly preferred embodiment and thus it picking a compound from the claimed list was not a selection per se. Therefore, the Examiner considered that a selection of the specific salt from the list combined with this compound would allow you to arrive at the claimed invention. As a result, the Examiner considered that only a single selection was required from D1, thus held that the claim was not novel.
The Board disagreed with the Examiner’s approach and highlighted that both the disclosure of the compound and that of the salt are in distinct and extensive lists in D1. In particular, the Board commented that whilst a claimed compound may be viewed as a highly preferred embodiment of the prior art, it cannot be considered an isolated embodiment unless it is disclosed in a narrower list or as an example. No specific examples or narrower lists containing the relevant compound were disclosed in D1. As such, the Board considered that isolating both the relevant compound and the relevant salt from D1 required a selection a list. In addition, the Board considered that a further selection had to be made to arrive at the claimed invention: choosing for the compound to be a salt thereof rather than the free compound. Hence, three selections from distinct lists were required to arrive at the claimed invention. The Board determined that Claim 1 was novel with respect to D1.
This case emphasises that a feature that is claimed in a list of alternative features cannot be considered to represent a preferred feature unless it is disclosed as such.